3-D printing, or additive manufacturing, is a process of making three dimensional solid objects based on blueprints provided by digital files. The synthesis of the desired 3-D solid object is achieved by strategically generating successive layers of an additive material in a pattern on a platform of a 3-D printer until the entire object is created. The synthesis of the 3-D object is driven by the digital files that provide the specifications that describe how to create the pattern of layers and the materials used to generate the object. The digital files specifying the design are provided by the user, and the digital files read by the 3-D printer may include G-code files, computer-aided design (“CAD”) files, STereoLithography (“STL”) CAD files, or other file types generally used in additive manufacturing processes. In some instances, the digital files refer to a 3-D model of a new object, but alternatively, the digital files can refer to a copy of an object derived from the usage of a 3-D scanner.
The generation of the successive layers of the additive material can be performed, for example, according to any one of: (1) Vat Photopolymerisation, (2) Material Jetting, (3) Binder Jetting, (4) Direction Energy Deposition, (5) Powder Bed Fusion, (6) Sheet Lamination, or (7) Material Extrusion. Specific processes of Material Extrusion used to generate the successive layers can involve making sequential deposits using fused deposition modeling (“FDM”), fused filament fabrication (“FFF”), or Direct Ink Writing (“DIW”).
The materials used as the “ink” of the 3-D printer to generate the 3-D object can include, for example, any of: powder material, polymer material, thermoplastics, eutectic metals, edible materials, rubbers, modeling clay, plasticine, metal clay, ceramic materials, metal alloys, papers, composite materials composed of ceramics and metallic materials (“cermet”), metal matrix composites, ceramic matrix composites, photopolymers, plaster, stainless steel, aluminum, plastic film, and metal foil.
3-D printers are generally protected from external influences by a build cage, and, within the build cage, the 3-D printer includes at least a build platform on which the synthesis process is executed. Before building (printing) a 3-D object on the build platform, the build platform (or build plate) should be set to a level state.
Particularly in applications in which the accuracy of the 3-D object generated is of concern, the initialization process and achievement of a level state build platform is crucial. Moreover, in some applications, the build platform must not only be initialized to a level state, but must also maintain a level state throughout the duration of the printing process despite the weight and or placement of the ink deposits on the build platform. Conventional build platform systems use either error correction techniques to compensate for a non-level build platform or rudimentary mechanical leveling techniques to attempt to achieve a level state of the build platform.
A first type of conventional build platform systems uses a sensor to sense unevenness of a build platform, and then, based on the sensed state of the build platform, alters code included in a digital file to compensate for the non-level build platform, which code is then executed for synthesis of the 3-D product. However, the final product generated based on the altered code is not desirable for some applications because, despite the code alteration, the base of the resulting 3-D object is not entirely flat. In addition, due to the offset of the pattern provided at the base of the 3-D object, additional offset error is propagated vertically throughout the entire printed 3-D object. This error occurs because the alteration provided in the code corrects for an error but does not actually fix the error in the level state of the build platform. The build platform itself remains in a non-level state throughout the synthesis of the 3-D object using the first type of conventional build platform system.
A second type of conventional build platform systems requires high levels of user interaction or skill. FIG. 1 is a perspective view of such a 3-D printer system 100 that includes an adjustable build platform. 3-D printer system 100 includes a surface 110, which is the top of a build platform 108. For an accurate printing process, the surface 110 should ideally be level relative to an extruder head 112. To level the top surface 110, supporting posts 102, 104, and 106 of the build platform 108 should be adjusted. The 3-D printer is generally enclosed in a build cage 114, which typically has a single access door near the front supporting posts 102 and 104.
FIG. 2 depicts a conventional process 200 for adjusting a build platform for this second type of conventional build platform systems.
As shown in frame 202, to place the build platform in a level state, a user manipulates a spacer 204 (e.g., a piece of notebook paper) to subjectively determine a gap height between the extruder head 206 and the build platform 208 at different locations on the printing platform. Typically, the different locations on the printing platform coincide with the locations directly above the posts 210, 212, 214 supporting the build platform. For example, frame 216 shows an adjustment associated with a front left post 214, frame 218 shows an adjustment associated with a front right post 212, and frame 220 shows and adjustment associated with a rear post 210.
After the user visually notes the presence of the gap (or the absence thereof) between the platform and the extruder using the spacer at the different sampled locations, the user then proceeds to manually adjust the build platform height by tightening and/or loosening a spring loaded screw associated with the post of the respective location.
In some contexts, the user gauges this subjective determination based on an attempt to slide the spacer between the extruder and the build platform. Based on the attempt, the user might determine, for example, that there is insufficient space to slide the spacer between the two elements, and therefore the post in that particular location should be lowered. To lower the post, the user manually turns a knob associated with the post (or the base of the post itself) counterclockwise until the leveling sheet fits between the two elements. A user might alternatively determine based on the attempt that there is too much space between the two elements (the extruder and the build platform), and therefore the post in that particular location should be raised. To raise the post, the user manually turns the knob associated with the post clockwise until the level sheet fits between the elements with some resistance. The manual tightening and/or loosening is performed independently for each of the posts. Generally there are at least three posts connected to the build platform.
The 3-D product generated by the second type of conventional build platform systems can, on some occasions, be relatively accurate, but ultimately the degree of accuracy is highly user dependent. An experienced user of the second type of conventional build platform systems is more likely than an occasional or novice user to achieve an accurate 3-D printed object. Therefore, consumer oriented or teaching-focused 3-D printers using the second type of conventional system are unlikely to reliably provide accurate objects. In addition, 3-D printers requiring regular re-initialization due to environmental factors (i.e., frequent usage, high traffic areas and/or vibrations from other machinery) are also unlikely to reliably provide accurate results. Initialization of the build platform according to this second type of system requires a large investment of time and is tedious.
Moreover, users of the second type of conventional build platform systems face an additional challenge that the build cage which encapsulates the build platform has an access door on only one side of the build cage, limiting access to all sides of the build platform, which makes access and manual adjustment of knobs associated with the rear side post particularly challenging.